1. Field of the Invention
The field of the invention relates to patient support apparatus such as stretchers and other patient handling equipment, and particularly to such apparatus including stabilizing mechanisms for preventing tipping thereof when a patient's weight is towards one end of the apparatus.
2. Brief Description of the Related Art
Patient handling equipment, such as stretchers and surgical tables and the like, have been designed for many uses. Such equipment may be capable of providing a full range of stretcher and chair positions, thereby providing a great deal of versatility.
Height adjustment of patient handling equipment is often provided through the use of one or more hydraulic column assemblies. Controls are provided for operating these assemblies. It is important that, upon use of the controls, the hydraulic column assemblies cause a steady ascent or descent of the patient support portion of the apparatus, whichever is desired.
The stability of patient handling equipment is another important consideration, particularly when a patient is supported by such equipment. By moving such equipment between stretcher and various other configurations, such as chair or obstetric/gynecological positions, the patient's weight is shifted towards one end of the equipment. This can cause the telescoping of the hydraulic column assembly at the opposite end of the equipment, typically the head end, unless it is in the fully elevated position. The negative load at the head end may also prevent this end from lowering properly upon actuation of the controls.
The problem resulting from the application of unequal forces upon a patient support apparatus have been recognized by the industry, and various approaches have been taken for addressing them. One approach for lowering a column assembly having a negative load thereon has been to manually exert a downward force at one end of the apparatus. The inconvenience associated with this procedure is readily apparent. A second approach has been to add weight to the head end of the unit for exerting a counterbalancing force. The mobility of the apparatus, however, is compromised by the addition of such weight.